Pilot or relay valve



Jam-15, 1952 H. ESCHER PILOT OR RELAY VALVE 2 SHEETSSHIEET 1 Filed Sept. 19, 1945 I H. ESCHER PILOT OR RELAY'VALVE Jan. 15, 1952 Filed Sept. 19, 1945 2 SI-lEETS-Sl-XEET 2 7// A I q not x x I u\ Patented Jan. 15, 1952 PILOT OR RELAY VALVE Hans Escher, Wollongong, New South Wales, Australia, assignor to Australian Iron & Steel Limited Sydney, New South Wales, Australia, a company-of New South Wales- Application September 19, 1945, Serial No. 617,285 InAustraliaNovember 14, 1944 1 Claim. 1

ency to hunting. This inventionis applicableto various types of controllers for the control of pressure and flow, as for example, flow ratio controllers'tocontrolalr in accordance with coke oven gas flow; ilow' controllers to control air in accordance withblast furnace ga flow; blast 'iurnace flow regulators which maintain a constant fiow-of blast furnace gas; coke-oven gas flow regulators similar in function to the last described example; and coke oven gas safety regulators which cut oft the coke oven gas when the pressure in the blast furnace gas is higher than that in the coke oven gas main, thereby preventing back 'fi'ow of the blast furnace gas into .the coke oven gas main.

The automatic regulator for blast furnaces, coke ovens and the like has associated with the control means a pilot valve consisting of a pair of valve members operated by a spindle in a valve body or the like over valve openings ionseatings at opposite sides or ends of such: .body,.and said seatings control an inlet from the main flow line or pipe or other connection and a discharge port respectively. A connection to said body from a servo motor or other unit'is provided for actuating the regulating valve, and an operative connection from the valve spindle to an impulse receiving element, second servo motor or the like, for actuating said spindle.

The valves have spring means associated therewith and are adapted to float freely in the valve body over their respective seatings, with a small gap therebe'tween, so allowing a small quantity of air or other fluid to pass through. In this condition the two gaps are then at their minimum, and the speed of regulation is also at 7 its minimum. When the pilot valve is thrown out of balance, one of the valve springs is de-' flected in accordance with the out of balance force, and the gap between the valve and its seating becomes greater as the out of balance force increases, and the speed of regulation is increased accordingly. When the desired regulated 2 point is-approached, the valves float freely and without friction in relation to the seatin'gs and their body, so that the greatest accuracy of-regulation is attained.

In order to describe the invention more fully,

reference will now'be made to the accompanying drawings wherein:

Figure 1 is'a schematic layout of an automatic regulating valve system embodying one form of the invention.

Figure 2 and 3 are sectional elevations of a preferred construction of'therelay or pilot valve, showing it in the large out-of balanceposition, and floating or small out-of balance position respectively.

The regulating valve 5 is mounted in the main supply passage 6 and connected by operative linkage 1, more or less as usual, to the bell 8 of a servo motor 9 which has a pipe connection 10 to the body I I of the pilotor relay valve meanslate'r described. An inlet pipe or passage 12 leads to the body ll. A'pump or other pressure supply or boosting source, (not shown) may be connected to the pipe 12 instead of the main supply passage 6. A discharge pipe l4 leads from the body II and there is also a "feed passage 15 connecting to an impulse receiving element It, constituted of-a second servo motor'andforming the primary controller, the bell I1 of which, is connected by an actuating arm IS with the spindle [9 of the pilotorrelay'valve; now to be described in detail.

The above described layout may be all more or less as usual, and the fluid used to operate the servo-motor 9 and the impulse receiving element I6 is taken from the main 6, the pressure in which is being regulated. The operating fluid can also be supplied by an 'outside'source.

The pilot or relay valve consists of a body ll with'an inlet chamber to which an inlet pipe [2 is, connected, and there is a sideward branch 21, the bore of which is preferably tapered inwardly, leading to a spindle compartment 22 flanked by valve openings 23 and 24, the outer faces of which form seatin'gs 25 ancl'26' with-a gap therebetween. The branch 21 has a pipe ID from the servo motor 9 connected thereto.

The valve spindle I9 being positioned more or less centrally, and free to move upwards and downwards without friction, has a medially enlarged stem portion 21, with shoulders 21A. The length of the stem portion 2'! is a little greater than the distance between the valve seatings 25 and 26. The end portions of said spindle l9 are reduced and screwed towards the extremities ating arm I 8 is rigidly afiixed the outer spindle 7 end and the nut 34.

In operation (see Figures 1, 2 and 3), when the desired regulating point ismaintained, the valve spindle l9 and the inlet and exhaust valves 28 and 29 float freely in the valve body, with the said valves over their respective seatings 25 and 26, and spaced therefrom by a small gap which allows only a small quantity of air or the like to pass the top and/or bottom gaps. These gaps are then at their minimum and the speed of regulation is also at its minimum. It will be seen from the drawings-that the springs 32- control the respective valves 28 and 29-and regulate the extent .of the gap, 1

With increasing out of balance force, as say, due to pressure in the main 6 decreasing, the impulse receiving element or primary regulator l6, through the depression of its bell ll, pulls down the actuating arm l8 at one end, thus ele- "vating the other end of said arm 18, and thrusting the valve spindle 21 upwardly, closing the exhaust valve 29 and opening the inlet valve 28,

thus allowing pressure to flow from the line I2 to the servo-motor 9, thereby resulting in increased speed of operation, and opening the regulating valve 5.

As the primary regulator .or impulse receiving element I6 approaches, balanced condition, the spindle I9 is lowered as the actuating arm 58 is depressed at that end, gradually reducing the gap'of the inlet valve 28, and so decreasing the speed of operation of the servo-motor 9.

In the case of out of balance efiect due; say, to increase of pressure in themain 6, the impulse receiving element 16 elevates one end of the actuating arm I8, thus depressing its other end and so pulling down the valve stem 21, closing the inlet valve 28 and opening the exhaust valve 29. Pressure under the servo-motor 9 is thus released and the regulating valve 5 closes. As a balanced effect is approached, the impulse receiving element l6 gradually restores the valve spindle 19 to the floating position.

It will be seen from the drawings that the maxi- .mum exhaust gap is fixed by the clearance between the valves 28 and 29, while the maximum inlet gap is fixed by clearance between the collars 33. The length of the spindle enlargement 21 between its ends or shoulders also-fixes the minimum gap.

Due to the small gaps between the valves and their seatings, the valves are responsive to immediate, opening of either the inlet or exhaust ports by a minute out of balance force. When the valve is in balance the small amount of pressure entering the inlet valve opening 23 through the gap, and at greater pressure than that in the pipe connection 10 and under the bell 8 of servo-motor 9, exhausts through the outlet valve opening 24 and through the gap at the same pressure, and at the same time, the pressure in pipe 10 remains constant.

Instead of the pipe 12 being connected to a pressure supply or boosting source as before described, it may be connected to an exhaust or suction element (not shown), and when the pressure in the main 6 decreases, valve 28, which now becomes the exhaust valve, opens, thereby closing the inlet valve and increasing the vacuum under the bell 8 which is suspended by a counterweight. In consequence, the bell is pulled down, and through the linkage I, it opens the regulating valve 5 which is set opposite to the position shown in the drawings.

When the pressure in the main increases, the valve 29, which now becomes the inlet valve, opens, thereby closing the exhaust valve and allowing air at atmospheric pressure to'enter and pass through the pipe l0, thereby decreasing the vacuum under the bell 8. Byvirtue of the counterweight the bell rises, and through the linkage l, the regulating valve 5 is closed.

I claim:

A pilot or relay valve comprising a body having a compartment therein, an inlet to said compartment, an outlet from said compartment, an opening to provide communication between the compartment and a servo-motor or other regulating valve control, an annular valve seating at said inlet, an annular valve seating at said outlet co-axial with and oposed to the inlet valve seating, a valve spindle extendingthrough said compartment and having reduced diameter ends externally of said compartment forming shoulders adjacent to said valve seatings,-a valve element having a tapered hole therethrough and slidably fitted on each reduced diameter end of the valve spindle with the smaller end of the tapered hole adjacent to the related shoulder of the spindle which provides an abutment for said valve element, a collar screwed on each end of the valve spindle, a compression spring located between each collar and valve element to bias each valve element towards its valve seating, and an actuating arm secured to the valve spindle at one end.

HANS ESCHER.

REFERENCES CITED Q The following references are of record in the file of this patent:

UNITED STATES PATENTS Date' France of 1935 

